JPS60138488A - Electromagnetic type launcher - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (19) The present invention relates to an electromagnetic projectile launcher, particularly to a capacitor-driven multi-stage augmented parallel rail launcher.

Electromagnetic projectile launchers can accelerate various projectiles at high speeds.

Some applications for electromagnetic launchers require the launcher to accelerate the projectile to extremely high speeds. For example, at least 50 Km/s for inertial fusion experiments involving kinetic energy conversion to obtain the temperature and pressure required for the fusion reaction.
It is assumed that a minimum speed condition of c is imposed. A simple parallel rail launcher capable of achieving these speeds or higher can reach several hundred meters in height, and because of this length, and to increase efficiency, a multi-stage power supply is required. It would be preferable to adopt The current must be as low as possible to reduce rail degradation, and the current must flow over a relatively short distance to increase efficiency. Multi-stage launchers have already been proposed that limit the distance over which the projectile firing current flows. Hawke et al. (1982)
U.S. Patent No. 4, issued August 10, 2013. ．． No. 343,223 discloses a multi-stage rail method. However, this known rail method utilizes precisely timed switching to power successive firing stages, or an extinguishing structure that extinguishes the driving arc at the end of each stage and generates a new arc in the next stage. We need a means to do so.

It is an object of the present invention to provide an electromagnetic projectile launcher that reduces the required firing current and limits the distance over which the firing current flows.

Broadly speaking, the present invention includes a first pair of substantially parallel conductive rails, a conductive magnet that, when actuated, conducts current between the first pair of rules to propel a projectile along the rails; a plurality of firing stages are formed by segmenting one rail of the pair of conductor rails, and are disposed near at least one of the stages formed by the first pair of conductor rails and connected to the first pair of conductor rails. and an auxiliary conductor connected to a flesh tone power supply, each of the auxiliary conductors being configured such that current flows in the same direction as that flowing through the adjacent rail of the first conductor rail pair. To provide an electromagnetic projectile launcher that

An electromagnetic projectile launcher constructed in accordance with the present invention includes a pair of substantially parallel conductive projectile launch rails, means for conducting electrical current between the rails to propel the projectile along the rails, and a launch stage. and capacitive power supplies connected at stepwise locations along the rail for sequentially supplying current to current conducting means passing through the rail. The launch stage may be formed by dividing at least one rail of the conductive projectile launch rail and connecting each capacitive power source to each rail segment. Each capacitive power supply discharges when the current conducting means reaches the respective stage. An auxiliary conductor is disposed proximate at least one stage to provide the necessary inductance for power conditioning and to increase the projectile propulsion field. If an auxiliary conductor is not used, an inductor can be inserted in series with each capacitive power source for power regulation.

The multi-stage parallel rail launcher of the present invention connects a pair of auxiliary conductors in series with a pair of projectile acceleration rails in at least one launch stage, so that the current flowing through the auxiliary conductors increases the magnetic flux density between the projectile acceleration rails. A method of accelerating a projectile is adopted, which is characterized in that the projectile is propelled within the projectile membrane by increasing the current and passing a current through the rail and the auxiliary conductor. The present invention also includes within its scope a launcher that utilizes the propulsion armature as a switching element to directly and sequentially automatically trigger and synchronize the power supply to each launch stage from an auxiliary power source. In other embodiments in which the projectile launch rail is not segmented, switching means must be provided to sequentially connect the capacitive power supply to each launch stage each time the projectile reaches a particular point along the launch rail.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the accompanying drawings, FIG. 1 is a block diagram schematically showing an electromagnetic projectile launcher constructed in accordance with an embodiment of the present invention. This embodiment consists of a pair of substantially parallel conductive projectile launch rails 1.
Contains 0.12. The rail 10 is divided into segments 10a, 1ob for the first and second stages of the launcher, respectively. The surface of the insulator 14 along the inner diameter surface of the launcher coincides with the inner diameter surface of the rail 10, which faces the inner diameter surface of the rail 12. It is a conventional metal or plasma armature 16 that serves as the electrical conduction means between the projectile launch rails 10.12 and as the means for propelling the projectile along the rails.

Rail segment in the first stage of the launcher) 1'o
An auxiliary conductor 18.20 is disposed in the vicinity of a and a portion of the rail 12, and the adjacent projectile is emitted. This supplemental parallel current increases the magnetic flux density between the projectile launch rails. A capacitive power supply 22, including a series circuit of a capacitor bank 24 and a firing switch 26, and a rectifier bank 28, which acts as a crowbar device, is connected to the first stage of the launcher. The second stage of the launcher includes an auxiliary conductor 30.32. Connected between the auxiliary conductor 30 and the projectile launch rail 12 is a capacitive power supply 34 that includes a capacitor bank 36 and a rectifier bank 38 that acts as a crowbar. A diode or diode array 40 acts as a rectifying means and conducts the projectile firing current from the first stage to the second stage as the armature 16 moves beyond the first stage. Although only the first two stages of the launcher are shown in Figure 1, the number of stages may be increased to achieve the desired firing speed level.The operating mode of the launcher shown in Figure 1 is as follows. explain.

When it is desired to fire, all capacitive power supplies are precharged to the optimum voltage by means of a known charging means (not shown), thereby obtaining the required amount of firing current which varies with time and barrel location. The projectile may be loaded in advance as shown, and firing is started simultaneously with opening of the firing switch 26 of the breech power source. Depending on the exact circuit parameters, the current reaches its maximum level after, for example, tens or even hundreds of microseconds, at which point the capacitive initial stored energy is absorbed by the inductance of the first stage auxiliary conductor and at a particular point in time the projectile current Jfr is first accumulated in the additional inductance given by the length of the firing rail conducting the . As the projectile is propelled, the current changes depending on the location of the gun barrel, as shown in the fjSz diagram.

It should be noted that while the crotch or rail gap rectifier 40 prevents current from flowing back toward the breech, forward current is blocked by an open circuit at the muzzle end, so that the second It is impossible for a stage power source to release energy faster than intended. Therefore, the capacitor array in the power source of each stage cannot generate a reverse current toward the gun breech due to the action of the rectifier 40 consisting of a diode. If the number of stages is larger, the charging voltage of the capacitor array is gradually increased toward the muzzle, thereby reducing the forward current toward the muzzle. However, as soon as the projectile armature or drive arc straddles the second stage rail segment, the second stage current automatically begins to flow and increases again to its maximum value. The time required to reach full stage current can be reduced across the high speed stages near the muzzle end by lowering the series inductance and capacitance. In FIG. 2, point A represents the breech end of the launcher shown in FIG. 1, and curve 42 represents the first stage power source 2.
2 represents the projectile drive current supplied by . At point B, the armature or drive plasma reaches the second stage rail segment lOb, and curve 44 shows the contribution of the second stage current. The actual drive current 46 is equal to the sum of the current supplied from the first stage power supply and the second stage current. If the maximum current level provided by the first stage power supply is the maximum allowable given the mechanical and/or thermal constraints of the gun barrel and projectile, then the current peak in each stage must be must have approximately the same value. Also, the force acting on the projectile is proportional to the square of the current, and the effective value of the current (
rms), the greater the average force and therefore the shorter the time required to reach the required speed. For a given peak current, the rms value increases unless the minimum drive current decays too much, which requires the system to supply the next stage current as soon as the total drive power decays to the lower acceptable limit. Just set it.

Each capacitive power supply capacitor is a passive rectifier 28.38
However, other crowbar methods may be used. For example, the capacitor may be shorted by appropriately triggering the ignitron to prevent it from recharging during the acceleration sequence. The illustrated rectifier configuration is considered preferred because it eliminates the need for a crowbar switch control circuit. It is also possible to operate each RLC circuit in overbraking mode without using a crowbar, but this method has low efficiency, takes a long time to reach the maximum current peak, and limits the range of application of the device. be done.

For example, inertial confinement fusion
ion), arc drive is used, and the mass to be accelerated is as small as, for example, 2.5 grams, even including the sealed gun cavity and the rigid bottom plate, so arc drive is used. Since, the projectile is accelerated by a single armature current path, only extrapolation means need be employed in this scheme.

To demonstrate the advantages of the multi-stage capacitor-driven self-boosting launcher of the present invention as shown in FIG. The device parameters were calculated assuming ideal conditions where the device is located at Intended firing speed 50k
m/Sec, the total propelled mass is 2.5 grams, the tlI radical current is 100,000 amperes rms, and the inductance of the projectile launch rail alone is 0.5 microHenry/m. In this case, the required gun length is 1
It is 250m. As shown in FIG. 1, this gun length can be calculated to be reduced to approximately 417 m by simply employing a single extrapolation means. If a double extrapolation method is adopted, the gun length will be further reduced by approximately 2
Shortened to 50m. With a gun length of 250 m, to achieve the same rate of fire without employing extrapolation means, the propulsion current must be increased by 2.
Must be increased to 24,000 amps rms. The high currents required without extrapolation significantly increase resistive losses, accelerate rail deterioration, and require the number of parallel rectifiers to be increased by a factor of about 2.25, which increases the Stiffness increases.

FIG. 3 is a diagram schematically illustrating a multi-stage capacitor-driven electromagnetic launcher incorporating extrapolation means in the second stage in accordance with another embodiment of the present invention. In this embodiment, an inductor 48 is inserted in series with the second stage capacitive power supply 34 to store energy and regulate the amount of power. This function may be performed by a busbar configured to have the required inductance. Such a stage power supply 34 using an external series inductance is preferably employed at the muzzle side, with auxiliary conductors at or near the breech rail stage for inductive energy storage and current control.

In a device provided with extrapolation means as shown in FIG. 1, the auxiliary rail not only performs both this energy storage and current control function, but also utilizes its own magnetic flux to increase the force acting on the projectile.

In the launcher of FIGS. 1 and 3, a rectifier 40 is provided only at the breaks or insulation gaps between the segments of the launch rail lO.
are arranged, and the launch rail 12 is seamless. However, if a similar cut exists in the launch rail 12, a rectifier in the opposite direction may be added to be on the safe side. In this way, even if the rectifier fails due to a short circuit, the function of the device will not be affected. That is, as long as at least one rectifier operates normally in each segment gap pair, the rectifier acting as a short circuit between the insulation gaps will prevent normal operation of the launcher even if the other rectifiers fail. A very important feature of the multistage launcher shown in FIGS. 1 and 3 is that all switches except the launch switch 26 can be omitted.

The capacitive power supplies in all 9, except the breech power supply, are triggered by the armature or arc 16 reaching and shorting the origin of the respective propulsion rail cavities. If more favorable firing rate control is desired, one can intentionally reach an excess velocity and then brake all or some of the final capacitive stages, or switch to prevent one or more of the final stages from initiating discharge. or by switching to reduce the current from the power supply of any stage.

The invention targets extremely high speeds, such as those sufficient to approach inertial confinement fusion conditions, in relatively small caliber launchers, but it is an expensive and relatively dangerous method of propulsion. It can also be adapted to lower velocities such as those obtained with two-stage gas guns. Further, the extrapolated rail launcher of the present invention can also be used at low speeds for accelerating a relatively large mass within a relatively large barrel. A sliding metal armature is preferred in this case, and an interpolation arrangement may be employed to achieve the required high forces at moderate current levels.

The launcher of FIGS. 1 and 3 in which rectifier 40 straddles insulator 14 is considered to be a preferred embodiment of the invention. However, if the residual energy is inductively stored in the rail stage that the projectile has just passed, then the rectifier 4
0, the launcher can also be activated by arcing between the rail gaps or the insulators 14. In an alternative embodiment, the launcher can be operated without such arcing if the dielectric armature decays the current to zero or cuts off the current to zero before proceeding to the next stage. In this case, a dielectric metal armature is used to prevent arcing that shorts the rails. It goes without saying that this method, where the current is zero, results in a current with an undesirably low rms.

FIG. 4 is an explanatory diagram schematically illustrating an embodiment of the present invention in which the launch rail 1O112 has no discontinuity. This embodiment requires very precise timing to sequentially trigger successive capacitive power supplies. This is because if the power is applied too quickly, the current can flow backwards and decelerate the projectile, with serious consequences. Therefore, a switch or other closing means must be provided in series with each capacitive power source, except for the breech power source, to act as a means for connecting the power source to each stage.

The operation of this switch must be precisely controlled so that it senses the position of the armature 16 and connects the power source 34 to the second stage of the launcher when the armature reaches a predetermined position along the launch rail 10.12. A sensor 54 is provided for generating a signal for controlling the operation of the switching means 52.

The factor limiting the final velocity of the Wooden invention's capacitor-driven multi-stage electromagnetic launcher with auxiliary rails is due to dielectric breakdown in the intervening space or, more likely, premature surface breakdown of the insulator that confines the muzzle along with the propulsion rail. This is thought to be caused by excessive voltage breakdown. In the case of a fully automatic triggering scheme, such destruction may occur between capacitor charging and actual firing, or in the path of the accelerating projectile. In either case, the parasitic arc moves towards the muzzle, triggering the power supply in each stage to discharge,
As a result, the desired rate of fire cannot be obtained. Such anomalies often occur in the high-speed gun barrel region where the charging voltage of the capacitor must be gradually increased, so that the back emf of the driving armature or arc is extremely high, e.g.
In the case of a double reinforcement configuration of 0 kiloampere and 50 km/sec, stage energy is rapidly released even though it is about 12.5 kilovolts. The exact amount of limitation imposed by this tendency to premature arcing depends on a variety of variables. For example, muzzle size, rail surface conditions,
Type, condition, cleanliness and shape of the insulator, vacuum or gas atmosphere, duration of high voltage, voltage gradient in space and in the insulator, presence of particles, etc.

Several novel means are conceivable to sustain the possible output and therefore speed of the present invention. These methods include the following: 1. A meter switch is separately installed in series with a capacitor on the high voltage stage on the muzzle side, as shown in Figure 4, just before the projectile reaches each stage rail. This switch should be closed. This limits the time that voltage is applied across the rail gap and reduces the likelihood of premature dielectric breakdown.

Below Margin 2, the final or fast stage is intentionally operated at a low current level, thereby reducing the back emf and therefore the required capacitor charging voltage.

3. Reduce or eliminate the boost to the final or high speed stage, thereby also reducing back emf and therefore capacitor voltage levels.

4. A rail configuration as shown in FIG. 5 is practical if the dielectric armature can be operated at very high speeds with a sliding conductor or with a very short arc from the armature to the rail. In this configuration, the launch rail 10.12 is provided with a longitudinal groove for guiding the armature and projectile package. This results in a long surface insulation path 58
．． This provides flexibility in the design of the insulator 60 and suppresses heating and deterioration of the insulator. All of these factors prevent flashover of the insulating surface.

When adopting means 2 and 3 described above, the capacitor is charged to a low voltage to prevent forward current from flowing from the high voltage l<n to the sequentially arranged low voltage banks faster than a predetermined time, The interstage commutator 40 can be configured between three poles that are triggered into conduction as soon as the drive arc or armature respectively straddles the rail gap. This means can also generally be employed instead of an auto-trigger diode. As another means of preventing such forward currents into the granule capacitors, series rectifiers may be provided for capacitor strings that may be affected by such forward currents.

In summary, the launcher of the present invention has the following advantages over known high-velocity electromagnetic projectiles: 1. The required high acceleration forces can be obtained at relatively low propulsion current levels; reduces rail and insulator wear, reduces resistance loss,
It is expected to reduce switching and commutation complexity and cost, rail heating, and busbar weight.

2. In an ideal automatic triggering scheme, there is no need for switch timing.

3. Because of the high acceleration forces available, relatively short launchers and relatively short acceleration times can be employed compared to configurations without boosters using the same firing current.

4. In the boost configuration, current control and temporary energy storage are provided by the auxiliary conductor, eliminating the need for separate expensive high current inductors to perform these functions. Furthermore, the magnetic flux of the auxiliary conductor, which stores energy, also significantly increases the acceleration force on the projectile.

5. As with other multi-stage power systems, there is no need to conduct high currents over long barrel lengths, except for some of the final stage energy that is dissipated in the circuit spanning the muzzle.
The projectile can be propelled by discharging and supplying the energy stored in each stage without waste.

Relatively short high current buses, short effective current conducting rail lengths, and nearly complete discharge of stage inductive energy all lead to increased overall energy efficiency.

As is clear from the graph of FIG. 2, the current increases rapidly, and this tendency is particularly noticeable in the single boost launcher shown in FIG. Especially when the firing stage is short, the initial inductance is low in this configuration, so the oscillation frequency before the crowbar is relatively high, and the current rises accordingly. In a multiple boost configuration, and with relatively long stages, the oscillation frequency can be much lower, resulting in a much slower current rise in each stage, which also helps maintain projectile integrity. This is considered preferable in order to reduce the adverse effects associated with increased current density due to the skin effect on the rails and busbars. The aforementioned adverse effects, such as local overheating and excessive resistance, can also be reduced by using multistage transposed drive and boost conductor rails.

Although the invention has been described in connection with preferred embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the scope of the invention. It is therefore intended that the claims encompass all such modifications.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram of an electromagnetic projectile launcher constructed in accordance with one embodiment of the present invention. FIG. 2 is a graph of the electrical current that appears in the launcher of FIG. 1 during firing. FIG. 3 is a simplified diagram of another embodiment of the invention. FIG. 4 is a simplified diagram of yet another embodiment of the invention. FIG. 5 is a cross-sectional view of a projectile launch and augmentation rail that may be utilized with the launchers of FIGS. 1 and 4. FIG. 10, 12... Rule 16... Armature 18.20.30.32... Auxiliary conductor 22.34.
... Capacity power supply 24.36φ ... Capacitor row 26 ... Firing switch 38 ... Rectifier row

Claims (1)

[Scope of Claims] 1. a first pair of substantially parallel conductor rails, a conductor magnet that conducts a current between the first pair of rules when actuated to propel the projectile along the rails; A plurality of firing stages are formed by segmenting one rail of the pair of rules, and the firing stage is disposed near at least one of the stages formed by the pair of rules. and an auxiliary conductor connected to a flesh tone power supply connected to the auxiliary conductor, and each of the auxiliary conductors is configured such that current flows in the same direction as that flowing through the rail of the adjacent second rule pair. Features an electromagnetic projectile launcher. 2. The electromagnetic projectile launcher according to claim 1, wherein a rectifying means is inserted between adjacent segments of the segmented rails of the first conductor rail pair. 3. The electromagnetic projectile launcher according to claim 1 or 2, wherein a crowbar circuit is connected to both ends of each of the capacitive power sources. 4. The at least one power source is capacitive, and an inductor is connected in series to at least one of the capacitive power sources, according to claim 1, 2, or 3. electromagnetic projectile launcher. 5. The current conducting conductor includes a metal armature, and the first conductor rail pair includes mutually opposing elongated grooves for guiding the metal armature. The electromagnetic projectile launcher according to any of items up to 4. 6. An insulating material is placed between consecutive segments of the segmented rail, and one surface of the insulating material is coincident with a surface of the segmented rail that faces the other rail of the second rule pair. An electromagnetic projectile launcher according to any one of claims 1 to 5, characterized in that: